Road finishers or asphalt finishers are construction machines for producing asphalt surfaces, also known as pavers. In operation, the road finisher distributes and smoothes bituminous paving material, and may also compact the same. For this, the road finisher basically is equipped with a screed plate for smoothing the paving material, and a tamper bar for pre-compacting the paving material before it is smoothed. In order to prevent sticking of the bituminous paving material to the paving device, heating devices are employed which heat up the tamper bar and/or the screed plate and which may be implemented on the tamper bar and/or the screed plate, for example, as a multi-layered structure of heating layers applied by thermal spraying.
US 2015/0037097 A1 discloses a road finisher comprising a screed plate and/or tamper bar wherein a heating layer is applied to the screed plate and/or tamper bar by thermal spraying.
However, the solutions known from prior art for heating the tamper bar on the one hand are rather expensive, and on the other hand, require a rather complex production procedure. Since the tamper bar with its tamping surface is subject to high stress, it usually has to be replaced after a certain operating period and thus, together with it, the entire heating device connected thereto has to be replaced too, thus increasing the maintenance costs of the road finisher.
Also, it is only possible to arrange the heating device or to apply the heating layers into a corresponding recess on the backside of the tamper bar opposite to the tamping surface in order to avoid damage or even destruction of the heating device during operation, when the tamping surface hits the ground with high pressure. Thus, the positioning possibilities of the heating device are restricted, since it requires a protected area, whereby possibly even additional protection means may have to be provided. The restricted freedom of positioning may cause, for example, an adverse non-uniform heating-distribution or the generation of hot points next to the contact surfaces as well as rather long heating-up times until the tamper bar has reached the desired operating temperature. Finally, with the known arrangements of heating devices at tamper bars of a road finisher, also high material costs are created, since the entire tamper bar has to consist of a heat-treated material.